Early rehabilitation as a key predictor of improved functional capacity after heart transplant

Background Exercise-based cardiac rehabilitation (CR) improvesoxygen peak uptake (VO2peak) after heart transplantation (HTx), yet the optimal timing for its initiation and the impact of demographic factors (e.g., age, sex) on this response require elucidation. Objective To compare the effects of early versus delayed initiation of CR on VO2peak in patients after HTx. Methods In this longitudinal observational study, HTx recipients were allocated to a cardiac rehabilitation group (CRG) or a control group (CG). VO2peak was assessed at three points: pre-HTx, post-HTx before CR/pre-CG, and after CR/CG follow-up. The CRG underwent a 16-week supervised program combining aerobic and resistance training. Controls, unable to join CR due to logistical reasons, were identified retrospectively. Linear regression was applied to identify predictors of VO2peak improvement. Results Twenty-nine participants were analyzed (CRG n=18; CG n=11). Mean age was 48±15 vs. 49±13 years (p=0.971), with 78% and 81% men, respectively (p=0.532). CR began after a median of 45.5 days (IQR=67). Multivariate regression showed time to start CR, age, and sex as significant predictors of VO2peak improvement (R=0.713, p=0.014; R2=0.512). The CRG showed greater VO2peak increase than CG (5.54±0.84 mL·kg−¹·min−¹; p<0.010), with a significant between-group difference at Time 3 (5.16±1.95; 95% CI: 1.33–8.99; p=0.008). Conclusion Early initiation of CR was a key, modifiable determinant of superior VO2peak improvement after HTx. These findings suggest that prompt inclusion into structured, individualized exercise programs should be prioritized to optimize functional recovery